


#SurpriseKnot

by KaliopeShipsIt



Series: Alliteration-Verse [6]
Category: Teen Wolf (TV)
Genre: Accidental Knotting, Breeding Kink, Derek Has No Clue About Were-Biology, Established Relationship, Implied Mpreg, Knotting, M/M, Stiles Reads Too Much Fan Fiction
Language: English
Status: Completed
Published: 2014-04-07
Updated: 2014-04-10
Packaged: 2018-01-18 11:17:31
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings, No Archive Warnings Apply
Chapters: 2
Words: 14,760
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/1426519
Author URL: https://archiveofourown.org/users/KaliopeShipsIt/pseuds/KaliopeShipsIt
Summary: <blockquote class="userstuff">
              <p>Stiles is a passionate Alpha-Omega Supernatural fan fiction-reader and decides, much to Derek's horror, to explore his newly-developed breeding-kink in an elaborate knotting fantasy, starring Derek as the powerful Alpha-breeder. An initially reluctant Derek gets more into the spirit of things than either of them expected and suddenly Stiles finds himself frantically reading up on another, special genre of fan fiction ...</p>
            </blockquote>





	1. (K)not What I Was Expecting

**Author's Note:**

> Please do not put my stuff on Goodreads. I was not aware that part of my stories were on there and I am not comfortable with having my fan fics circulated out of my control. 
> 
>  
> 
> This work should be taken as lovingly tongue-in-cheek and is in no way intended to shame people who read Mpreg or Alpha/Omega as, looking at my own AO3 reading history, that would just mean shaming myself ;-).

It was a lovely, warm summer evening and Sheriff Stilinski felt completely at ease as he stepped onto the front porch.

It had been a rather uneventful shift and he had managed to get caught up with a lot of paperwork.

There were no murderers or troublemakers running around in Beacon Hills tonight. It was a rare occurrence and the Sheriff cherished it.

What he cherished even more was the fact that he had spotted his son’s jeep in front of the house as he turned onto their street.

Although he definitely didn’t mind getting to eat gloriously unhealthy food without his kid’s watchful, judgmental eyes boring into him on a regular basis, he really missed Stiles whenever he was away at college.

The frequency of his home visits had slightly lessened since his Freshman year and part of that was of course due to Derek Hale, his son’s broody, intimidating, and utterly besotted boyfriend.

Who was also a werewolf, but the Sheriff tried his best to block that part out.

He was well aware of what was going on in Beacon Hills and he was grateful that Derek helped him out whenever a supernatural situation threatened to get out of hand and risk the lives of the citizens he had been sworn to be protect, but the less he saw of glowing red Alpha eyes, the better.

Melissa McCall had embraced the news of her son’s transformation better than he had, he realized that, but then again, the mysterious forces in the town had lived under her roof. And eaten her food. And, occasionally, destroyed her furniture in Allison-inspired fits of rage.

The Sheriff, on the other hand, had been able block it all out much better. His kid was human and the fact that Alan Deaton referred to him as a spark did not bother the elder Stilinski much.

Stiles had gone through a terribly awkward phase of performing magic tricks when he had been six.

Even Claudia, who had considered Stiles’ attempts to cut holes into all of his socks just to see what would happen as the earliest signs of a future PHD in physics, had admitted that their son couldn’t do magic tricks if his life depended on it.

All in all, the Sheriff wasn’t really concerned.

Derek Hale had forced him out of his comfort zone a little more.

There had been a very awkward and tense discussion after he had first caught Hale and his then 17 and a half-year-old son making out on Stiles’ bed.

He had called his sister in Mississippi, who had suggested that he allow them to close the door while they were in the room together but that one of them always had to whistle.

That way, she had reasoned, they would not be able to make out again.

Derek, as it turned out, whistled loudly, but terribly off-key.

Which was no wonder, given the fact that the Sheriff had found his son’s lips attached to the werewolf’s privates when he had stormed inside the room to beg them to stop the whistling.

His sister had _not_ gotten a Christmas card in the mail that year.

These days, however, Derek and his quasi-father in law were mostly getting along just fine. Even if he did drive up to see Stiles at college almost every weekend, which left Stiles less time to see his old man.

On the one hand, the Sheriff found it hard not to feel some sort of resentment for Derek for stealing his son away from him.

On the other hand, he had never seen the kid so happy.

Which, all in all, made the situation much more acceptable.

Sheriff Stilinski smiled in anticipation as he opened the front door, smile turning into a half frown as he almost stumbled over Stiles’ sneakers.

Some things never changed, apparently. Grumbling, he put the shoes where they belonged and went into the kitchen, fully expecting to find his son munching on a Tofu burger or anything else that was unbearably healthy.

The kitchen was empty but there was a bottle of wine sitting on the table.

It had become part of a tradition that Stiles would bring home a bottle of good wine whenever he came to spend the weekend.

His college was close to one of the impressive California vineyards and enjoying a glass of wine over dinner or in front of the television had become a bonding ritual for the Stilinski men.

The Sheriff greatly enjoyed it, especially because it was something that was only for him and Stiles. Derek didn’t drink normal alcohol since he didn’t see the point of it when it wouldn’t affect him in any way.

In the new glorious era of Sterek – he had overheard Scott refer to them by this moniker one afternoon and although he did not understand this new trend of matching up names to refer to a couple he found the description somehow fitting, seeing how attached at the hip Derek and Stiles were – things that belonged only to him and Stiles were rare and hard to come by.

It was almost eight and Stiles had probably eaten already, so the Sheriff went and set two glasses on the table.

He was rummaging through the cutlery drawer in search for the corkscrew, when an unmistakable growl reverberated through the house.

The Sheriff knew it was just his imagination but he could have sworn that he saw the glasses rattle and move.

His canine quasi son-in-law sounded pissed, even more so than usual.

His fatherly instincts perked up and he briefly considered abandoning the wine and going up to see if he could help sort the situation out, when Derek’s next words stopped him cold.

“You want me to do what?! With my dick?!”

Resolutely, Sheriff Stilinski opened the wine and chugged its content straight from the bottle.

Abandoning the alcohol was absolutely _not_ an option.

 

**********************

Stiles was a little afraid that he had broken his boyfriend. Who, after his little outburst, was currently sitting in front of him, hands frozen in midair, his jaw hanging wide open and just – staring at him.

His eyebrows had risen up to his hairline. If they went any higher, they would fly off his forehead and head towards Mars. Where they would attend Pigfarts and ride around on Rumbleroar’s back.

This was – regrettably – not the time for obscure pop cultural references that only a true Internet and Harry Potter addict would understand.

He debated whether or not he should poke Derek with a stick to get a reaction out of him. The way he had just frozen in a rigid stance and wouldn’t let it go greatly unnerved Stiles.

If his voice had been as majestic as that of Idina Menzel, also known as Adele Naziim, he would have broken into song.

Instead, his foot carefully nudged Derek’s. His left eyebrow twitched. He hadn’t broken him after all.

“Derek, come on! It’s really not as bad as it sounds. I’ve read some really awesome fan fiction about it and it can be totally sexy, I promise. Someone even wrote a story about two players of the Spanish national soccer team doing it and those guys are super manly and win every single tournament – which has made the whole thing super boring and predictable by the way – and if they can do it, so can we.”

Derek’s right eyebrow twitched. Stiles was encouraged by the progress.

“Obviously it’s not a real thing but that doesn’t mean we can’t pretend. I could read you some excellent Destiel fan fictions on the subject, and you can be all “I am emotionally attached to my car and I love pie and Castiel” and I can be like “We have a profound bond” and we could role play it with our clothes on before we try it out for real? I’ve got a kick-ass trench coat lying around here somewhere...”

This time, Derek’s entire face twitched. Including, thankfully, his mouth and his vocal cords.

“So let me get this straight, oh beloved boyfriend of mine”, he said slowly, dragging the word beloved to the point where it just sounded cynical to Stiles’ ears.

“Your unhealthy obsession with Alpha/Omega fan fiction and self-lubrication has led you to believe that the base of my penis turns into a knot, which I can use to breed your digestive tract full of cubs, and you want me to do a running-commentary about my breeder-prowess while I am mounting you with said enormous knot?”

Stiles grimaced. When put that way, the whole idea sounded terrible and not the least bit sexy.

“That’s not ... I mean ... of course I know you don’t technically _have_ a knot. And I know I can’t get pregnant, I just thought that ... besides, stop mocking my appreciation of self-lubrication, it would be extremely practical.”

Derek pinched the base of his nose to stop himself from actually developing a headache, werewolf healing or not.

“Where would the babies even _go_ , Stiles?!” he asked, not taking his hands away from his face and instead massaging his temple in what he hoped was a rather clear message as to what he thought about the suggestion.

“You do not have a uterus and realistically, even if the breeding sperm created by this magical knot would manage to travel upwards in search of an organ that could grow and expand to the size of a small baby without killing you in the process, the farthest they would get would be your stomach, where they would be destroyed by the digestive acids. Not to mention that they would find nothing to merge with anywhere, thus rendering the entire point of conception moot, as I highly doubt the eggs from your breakfast burrito would work here. Forgive me for not seeing it, but where is the sexy in this scenario?”

“For heaven’s sake, Derek, there will be no babies! It’s called a kink for a reason! It’s all in our heads. You can’t claim that you have never felt the need to procreate, big strong Alpha wolf that you are. And I know we haven’t really had the whole starting a family/adoption talk yet, but, for the record, you would be an amazing dad who would be so wrapped around a little girl’s finger that you would find the meaning of life in attending Princess Tea Parties hosted by a five-year-old in a pink sparkly dress.”

Derek sputtered. “I’m stopping you right there, we are _not_ talking about my future daughter’s Princess Tea Party while your mind is stuck somewhere in the dark and forbidden corners of the Internet. In fact, we are done with this conversation. I don’t have a knot, I don’t have a breeding kink, and I am not going to do it. The end.”

Stiles sniffed in consternation.

“Remember last month when I hugged my roommate for his birthday and you came to see me that evening and proceeded to scent his cologne off of me until I thought your nose was actually going to leave a dent in my neck? And how you growled “Mine, all mine” for almost two hours afterwards, uninterrupted and with hardly any pauses to breath? And that’s just one of many examples for that little possessive-thing you’ve got going there, so I really feel you should indulge my potential kinks for a change.”

He gave Derek a calculating look. “I don’t even know if _I_ will enjoy it, to be perfectly honest, it might end up feeling too weird even for me and I might ask you to stop, but I really, really, want to try this and I am sure I can come up with many, many more examples of why you owe me to at least try it once.”

Derek sighed. The episode known as the Jealous-Rage-over-Birthday-Hug had really not been his proudest moment.

“Even if I was willing to try this – and I am not saying I am, this is purely hypothetical – where would we get a knot? I have more than a fleeting acquaintance with my dick and trust me, there is nothing there that would resemble a knot.”

Stiles had the nerve to actually leer at Derek. “After thorough research I feel that I can back you up on this observation. But you keep forgetting how receptive I am to suggestion my dear Sweetie Wolf. By the time the knot is supposed to make an appearance you will probably just have to say “Oh Stiles, there it is, my big fat throbbing knot” and I will totally believe you.”

Before Derek had a chance to say anything, Stiles corrected himself. “Only don’t say throbbing, it gives me evil flashbacks to really, really bad fan fiction. One must always be careful with the usage of the T-word. Especially when it is coupled with manhood.”

Derek shook his head in disbelief. “How do you even manage to keep your GPA as high as it is when apparently all you do is read fan fiction?” he asked, a tiny smile softening his features for the first time since the beginning of the conversation.

Stiles grinned. “A little mystery keeps the relationship alive. And besides, be happy that I am only making you try out this particular fan fiction stimulated kink of mine. I could have also demanded that you f…”

Before he got a chance to finish his statement, Derek had tackled him to the mattress and was proceeding to kiss him senseless, most likely in an attempt to shut him up. When they separated Stiles was looking adorably disheveled and Derek grinned, highly satisfied with his distraction technique.

“I really don’t even want to know,” he decided and Stiles grinned.

“Fair enough. How about this: you indulge me in my little breeding fantasy and I don’t complain about your next … say … twenty jealousy rages. Deal?”

Derek sighed. “I guess that sounds reasonable. I will go practice my throbbing-knot speech on your dad right now, you know how much I have come to value his opinion.”

Stiles smacked his werewolf on the head.

“I told you, there would be no vocalization of any throbbing sensations, pleasurable though they might be.” 

He smirked. “But I agree, we definitely need to get in the mindset of it, and it would help if you read some fan fiction, too, to prepare yourself.”

Derek groaned. “Must I?”

“You must. I just read this wonderful piece the other day …”

Derek made himself comfortable on the bed as Stiles hurried over to his computer to print out the story, babbling about literary prowess, master skills in characterization and amazing attention to detail a mile a minute.

He was quite grateful that he and Stiles could not reproduce naturally – a teenager with Derek’s temper and Stiles’ enthusiasm would have been a destructive force, indeed.

 

*******************

 

Derek considered himself a good boyfriend. No, scratch that, he considered himself the best boyfriend ever, because he was quite certain that a lesser man would have not been able to get through the fan fiction Stiles had chosen as his inspiration.

In order for him to get a good example of kink-acceptable dialogue, the story had had no plot whatsoever and had mainly consisted of lengthy knot descriptions and terrible metaphors.

Derek still didn’t know how he was supposed to fake the knotting part. He also didn’t understand why Stiles insisted on Dean being the dominant part in that relationship when it would have been clearly more believable with Castiel being the Alpha so to speak.

Not that he had spent a lot of time thinking about this, but being with Stiles occasionally meant being forced into _Supernatural_ marathons on a lazy Sunday and it had not taken him long to get a grasp of the characters.

His attempts to discuss the, in his opinion, glaringly out-of-character behavior of the story’s protagonists had been shot down by Stiles, who had informed him that he was clearly a) stalling for time, b) focusing on the wrong things and c) should better spend his time memorizing metaphors.

The glint in his eyes had led Derek to believe that Stiles had picked the story for the sole purpose of honoring the “True Poet of Beacon Hills and His Terrible Metaphors Fiasco” from two years ago.

All things considered Derek should probably consider himself lucky – at least this time, there had been no Twinkies involved.

Coincidentally, he had had more time to memorize them than either of them had initially planned, because Stiles had been dragged into a university project by his classmates a couple of days after their conversation and had been swamped with work ever since.

Derek, meanwhile, had been up to his ears in trying to help the Sheriff solve a suspicious case that involved kidnapped virgins and stolen jewelry and the chaos that followed the reveal of the perpetrator being an actual dragon had very effectively put the role-playing session out of his mind.

“A dragon?! What do you mean, a dragon? The one time I can’t come home because of class and you guys get to fight a dragon? Life is not fair!” Stiles whined over the phone one Wednesday evening.

Derek sighed. “It really wasn’t all that exciting once we had finally located it. It was rather tiny and we could easily overpower it. I swear the only highlight of that fight was that Scott got a bit too close when it started spewing fire and got his eyebrows burned off. It is not a good look for him.”

Stiles laughed and Derek smiled contentedly. He had missed the sound of this. They had not had much time to talk on the phone in the past weeks and when they had, either Stiles or Derek had been stressed out and their conversations had been rather short.

“We haven’t seen each other in almost three weeks, when are you coming home”, he asked and Stiles chuckled. “Awww, Sappy Wolf, you miss me! I was actually thinking about driving down tomorrow after class. We finally get to turn the project in at noon and if I skip classes on Friday, no one will care.”

Derek smiled. “Just don’t tell your Dad, he will not be happy about it.”

He could hear the grin in Stiles’ voice when he answered “Yes well, I was planning to spend tomorrow night at your place anyways. I hope you have not forgotten about our plans.”

Derek was proud to say that he managed to fight the urge to whine.

“Ah yes … The plans.”

“Now that was a pregnant pause if I ever heard one. Pun intended!” Stiles cackled and Derek groaned.

“Just how long have you been waiting to use this one?” he asked.

“Since before I asked you maybe?” Stiles replied enthusiastically, and Derek imagined that he could almost hear him high-fiving the air.

“I promise, it will be awesome! I have to go now though, we are going to go over the final revisions in a bit and I need to print this sucker out first. Sleep tight Derek.”

“I will see you tomorrow”, Derek replied, hoping that he sounded more enthusiastic than he felt.

He had missed his boyfriend, but he had also forgotten about the knotting-thing and he wanted to make Stiles happy, he really did, he just wasn’t sure he would be able to pull this off convincingly and without a snarky attitude.

It had taken a great deal of trust on Stiles’ part to even tell him about this fantasy and Derek readily acknowledged that, in retrospect, his response had not really been deserving of trust.

Not that Stiles had given any indication that he had gotten his feelings hurt but Derek, who was by no means a stranger to overanalyzing things, still felt a little guilty.

Derek wanted to make it up to Stiles in a satisfactory way and the thought of disappointing him because he could not pull of this performance made him more nervous than he would have cared to admit.

He also felt a little bad for his dismissive attitude of the whole thing in general. Stiles had certainly had a point when he had reminded him of the occasional scenting-frenzies Stiles allowed Derek to indulge in when he got jealous.

The whole idea of pretending to breed his boyfriend still felt weird to him, but it wasn’t terribly outrageous.

Derek had not really given much thought to the idea of having children with Stiles, but now his mind returned to the mental image of his future that Stiles had suggested and he couldn’t help but smile wistfully.

He was, and always had been, a family person and if his memories of Cora’s toddler days were any indication then Stiles was completely right. Derek would gladly attend any Princess Tea Party his daughter, or son, would invite him to.

Yes, Derek decided, after the role-playing session they would definitely have to have a talk about potential future family planning soon. 

And he was going to do his absolute best to give Stiles a night he would not soon forget.

*******************

When Stiles opened the door to Derek’s apartment the next evening, he was greeted with the smell of freshly baked lasagna, the flickers of candlelight, and an adorably nervous Derek, who was wrestling with the new bottle-opener Stiles had brought home from one of his trips to the vineyard.

Smiling fondly, Stiles approached Derek from behind and wrapped his arms around the older man’s midsection, burrowing his face in the crook of his neck and inhaling the comforting, familiar scent of his lover.

He pressed his lips to Derek’s sensitive skin and nuzzled him affectionately, then focused on the bottle, as his hands moved from Derek’s waist to take the bottle-opener from him and open the wine with practiced ease.

“A home-cooked dinner and wine? I feel special.” His tone was full of affectionate teasing and Derek smiled in response.

“What can I say, I’m just really glad to have you back.”

He turned around in Stiles’ embrace and captured the younger man’s lips in a soft, open-mouthed kiss. A thumb came up to stroke Stiles’ cheek and he tilted his head to deepen the kiss just like he knew Stiles liked it.

Stiles hands rested on his lower back and when Derek pulled back from the kiss and smiled one of his rare, carefree smiles at him, he laughed happily, feeling the tension of the last three weeks draining out of him.

His eyes fell back on the bottle and he whistled appreciatively.

“Not only am I getting wine, but I am also getting the good stuff. Impressive for someone who claims no interest in learning anything about wine culture.” He quirked his eyebrow at Derek and to his surprise, his boyfriend blushed.

“Yes, well, it goes well with the lasagna and you know, if tonight goes … uhm … successfully, then you won’t be allowed to drink it anymore for at least nine months, so …”

Derek trailed off, biting his lip and blushing even further and Stiles felt his pulse quicken at his words.

Before Derek could take his silence as a sign that he might have made a mistake, Stiles surged forward and brought their mouths together in another kiss, this one far less gentle and a lot more demanding than the last.

When he pulled back, his eyes were hooded with desire and his voice was a little breathless, when he said “I guess we better make it count then.”

As soon as Stiles began to eat with gusto, Derek seemed to visibly relax and dinner conversation was quiet and comfortable.

Not wanting to feel too full for the rest of the night’s activities, Stiles resisted the temptation of getting a second helping of lasagna and instead filled up his wine glass again, convincing Derek to try a glass himself, if not for the buzz then at least for the taste.

Derek nervously downed the glass in one gulp and Stiles exploded with laughter.

“I have so much to teach you!” he grinned, setting down his own glass and leaning over the table to pull Derek in for another kiss.

He could taste the wine on Derek’s lips and tongue and he made sure to kiss his boyfriend thoroughly, enjoying the intermingling of the familiar flavors. The hand that wasn’t grabbing Derek’s shirt was caressing his chest, worrying at a nipple through the fabric of his shirt and Derek groaned softly into his mouth, before standing up and hoisting Stiles out of his chair, somehow managing to never break the kiss.

They half-stumbled and half-dragged each other to the bedroom and when the edge of the bed hit the back of Stiles’ legs Derek gently lowered his back onto the mattress, his hands lightly trailing over Stiles’ abdomen before he pulled his shirt up and then over his head, carelessly tossing it to the side.

Stiles felt a familiar heat pull up inside him as Derek quickly straightened up to rid himself of his own shirt and then stepped between Stiles’ legs, which were still firmly planted on the floor.

Derek placed his hands on Stiles’ sides as he leaned down, trailing his lips down Stiles’ entire upper body and leaving feathery kisses all the way from his neck to his abdomen. 

He spent his sweet time there, his tongue dipping into Stiles’ navel and gently biting at the skin below.

Agonizingly slow he finally moved below Stiles’ navel, nosing at the waistband of his jeans and placing soft kisses all along the trail of hair that dipped into Stiles’ pants, his right hand moving from his side to gently trace circles over the younger man’s stomach.

Stiles wanted to arch off the bed, his dick desperately craving more friction than the tight confinement of his jeans, but Derek’s hands firmly kept him in place.

He tilted his head so that his eyes met Stiles’ and when he took in the flushed face of his lover he smiled with satisfaction.

“So eager to be bred, so eager to be filled with my cubs. Patience my love, I will make it worth your while.”

Stiles groaned, Derek’s words sending shivers all along his spine and he felt himself harden even further. He moaned, desperately needing Derek to move either his hands or his mouth and he thrust his pelvis up just as much as Derek’s firm hold on his stomach allowed him.

Derek responded by suckling at his hipbone, teeth gently grazing the skin as he finally set to work on Stiles’ pants, getting them open and then tugging them down his legs and feet.

Panting, Derek dropped to his knees in front of the bed. He used his hands to part Stiles’ thighs even further and allowed himself a moment to admire the sight of his boyfriend half-sprawled on the bed in from of him.

The outline of Stiles’ erection was clearly visible against the fabric of his boxer shorts, the tip peaking out above the waistband and Derek pressed an open-mouthed kiss to the black material, before he pulled them down with a swift movement and took Stiles into his mouth.

This time, Stiles did arch his back and he quickly propped himself up onto his elbows to steady himself and watch just in time as Derek pulled back and then dipped his tongue into his slit, before taking him in deep again and swallowing around his length.

Stiles made a keening sound in the back of his throat.

“Derek” he breathed, and Derek’s eyes met his, Alpha red beginning to seep through his irises.

His pupils were blown with desire and Stiles was so enraptured by the sight that he almost forgot what he was going to say – almost.

“Been too long … need you to stop, want to come with you inside me … ah … filling me up, breeding me, Derek, please!”

Derek’s eyes turned completely red and before Stiles could fully register what was happening, he had torn his own pants off, grabbed a bottle of lube, and was once again in the space between Stiles’ spread legs, this time paying attention not to his dick but to his ass, capable fingers teasing him and preparing him to take something larger.

Something as large as a knot, Stiles’ brain supplied helpfully and he moaned, imagining Derek’s gorgeous cock expanding at the base, stretching him wide and locking them together in the most intimate way.

The fact that this was actually not going to happen almost put a damper on his mood, but then Derek’s index finger grazed his prostate and coherent thoughts were no longer an option.

“Need you, want to feel you” he groaned, tugging at Derek’s hair and Derek leaned over the bed to kiss him again, one arm locked behind his back to steady him and the other grabbing the base of his neck.

Stiles lifted his legs off the floor and hooked them around Derek’s waist, feeling the tremors that were running through the older man’s frame. He pulled Derek closer with a smooth thrust of his thighs and Derek’s erection brushed against Stiles’ own, making them gasp into each other’s mouths in unison.

Derek broke the kiss and rested his forehead against Stiles’ for a second, the gesture loving and intimate and it made Stiles’ heart thumb in his chest even more.

“So perfect, so gorgeous, you will look so good carrying my cub” Derek breathed against him, the hand that was not holding his neck moving from his chest to his stomach, tracing across his navel and down to his pelvic bone, before he suddenly grabbed Stiles’ hips with both hands and hoisted him up so that he was essentially carrying him.

Stiles had never been more grateful for Derek’s werewolf strength and his dexterity when Derek climbed on top of the bed and lowered his back to the sheets in one fluid movement.

“Turn around” he all but growled and Stiles hurried to dislodge his legs from Derek’s waist, scrambling on all fours and, for a lack of a better term, presenting his ass to Derek, whose growl became even deeper.

“Mine, all mine, gonna breed you so good, gonna make the world see you’re mine!”

“Yours, Derek, all yours, want you inside me now, need you to come inside me,” Stiles replied shakily and it seemed to be just the right thing to say because Derek let out a sound that was somewhere between a growl and howl and buried himself inside Stiles with one swift stroke.

Derek’s left hand was gripping Stiles’ hip hard enough to probably leave a bruise, while his right hand was draped across his abdomen, pushing Stiles up and against him even as he pounded into him.

Stiles felt like his entire body was shaking and trying to come apart at the seams and the little that remained of his ability to concentrate was fully focused on keeping himself upright, as Derek picked up his pace.

This was nothing like the initially controlled thrusts he was used to, there was no licking and biting of his neck and shoulders, instead, Derek seemed to have somehow become unhinged, like a man on a mission, only able to focus on one task.

At present this task seemed to be slamming into Stiles as if his life depended on it and Stiles absolutely loved it.

He could no longer make out everything Derek was saying and when Derek dipped a finger into his navel and pushed down he came with a force that took him by surprise, spurting his release all over Derek’s hand and his own stomach.

Derek’s movements became jerky and he soon threw his head back and came with a stifled cry, collapsing forward and almost crushing Stiles into the mattress. His breathing was labored and Stiles could feel his heart pound at the point where Derek’s chest was pressed against his back.

He was struggling to support both of their weight and his muscles clenched involuntarily around Derek – who was growing hard again.

Only growing hard wasn’t exactly what it felt like, it felt different, wider somehow.

Wider – oh shit.

Stiles went perfectly still and when he heard the ragged breath above him, he could tell that Derek had also caught on to the fact that something was definitely going on when it most definitely shouldn’t.

“Uhm Derek?” Stiles all but squeaked, his tone much higher than he would have liked it to be.

“I think something’s wrong with your dick!”

 

*************************

When Stiles had entered his apartment Derek had still felt a little unsure about his part in their role-playing session, and he had tried hard and failed not to blush when he had told Stiles his reasoning for opening the bottle of wine.

Stiles’ reaction, however, had been very satisfactory and he had decided that as long as they were keeping it subtle and tender, without any too explicit references to magical knots and ass-babies, he could probably do this.

Heck, Stiles got him excited any day of the week and he had not seen his boyfriend in almost a month, so that should definitely help, too.

In retrospect, he wasn’t a hundred percent sure if his Alpha wolf instincts had been triggered by the unusual amount of attention he had devoted to Stiles’ abdomen while trying to get into character or the moment that he had actually uttered the words, but somewhere along the way his wolf had taken over and decided that breeding his boyfriend was not only a kinky fantasy, but actually a pretty wonderful idea and he had just – gone with it.

As he lay panting across his boyfriend’s back, Derek knew he should probably either move off of Stiles or at least lower them into a spooning position on the bed, but he had just experienced an orgasm that had quite literally made him see stars and he did not trust himself to move, let alone speak.

No, he decided, his open mouth pressed slightly against Stiles’ shoulder and his ears turning red as some of the things he had just told Stiles came back to him; speaking was absolutely overrated.

Instead, Derek listened to the soothing quick but steady heartbeat of Stiles and he had almost gotten his breathing back under control when his boyfriend suddenly went completely still under him and his heartbeat quickened.

Frowning, Derek tried to shift his hips, not wanting Stiles’ to feel too crowded in case he was having a panic attack.

He let out a shocked breath when he found that he seemed to be stuck.

Inside of Stiles.

What the hell?

He lifted himself up enough so that he was able to take a look at what was going on.

Granted, he couldn’t see much, but what he did see, combined with the strange feeling inside of his penis, made him a little nauseous.

His dick was not supposed to do that.

Why was his dick doing that?

More precisely, _what_ was his dick doing exactly?

“I think something’s wrong with your dick!” Captain Obvious squeaked under him and Derek was about to snap at him that yes, he could see that, it was _his_ dick after all, but then Stiles tried to move away from him in his panic and the tug caused Derek to arch his back with a low moan.

Upon hearing the moan Stiles’ tried to move again and the pressure around his unnaturally swollen erection was all it took to rip another orgasm from Derek.

Derek bit his lip so hard he could taste blood, his body felt like it was on fire and Stiles kept wriggling under him, sending bolts of pleasure through him that made his toes curl. Derek forced himself to grab Stiles’ hips hard, strong enough to keep him in place to stop him from moving.

“Stiles! You need to stop moving right now, you’re just going to end up hurting yourself and … Gaaah ... This is really not helping the … situation!”

Stiles stilled under him but Derek could hear his heartbeat going even faster.

“What _is_ the situation?” he squeaked and Derek grimaced, his sensitive ears not used to the high-pitch frequency of Stiles’ panic-voice.

“Stiles, _please_ , calm down. I … uhm … I seem to have actually developed a … a knot? I think?”

“You think?!” Stiles exploded under him and the jerky movement that accompanied the exclamation was enough to send Derek into his third orgasm within the past five minutes.

“Seriously Derek?!” Stiles exclaimed and he groaned at the pressure inside of him, which was slowly becoming more and more uncomfortable. Derek closed his eyes and breathed in deeply, trying to get himself into a headspace where he could actually calm his boyfriend down. When he felt halfway under control again, he carefully maneuvered himself and Stiles into a lying-down position, spooning him as he arranged them on the covers of the bed. Stiles was sweating against his chest and he could still feel the younger man’s muscles clenching around him, but his heartbeat was slowly returning to a more acceptable pace.

“Alright. One hour and it should go down, right? One hour. I can do that. Yep, I can do that.” Stiles muttered and Derek felt slightly guilty when he imagined how uncomfortable this probably felt for his boyfriend.

“I had no idea this would happen,” he murmured into Stiles’ ear, feeling very much at a loss as to what to do about the situation. There was no way he could pull out of Stiles without seriously injuring him in the process and the alien growth on his penis was still swollen and pulsating, making no effort to go down.

“I would hope that you had no idea this was going to happen,” Stiles huffed, seemingly more in control of the situation now that he had had some time to get used to it.

“My parents never talked to me about this and neither did Peter,” Derek explained and Stiles uttered a shaky laugh. “Just imagine how awkward that conversation would have been.”

They were pressed against each other in silence for a while and finally Stiles spoke up again, his tone contemplative. “You really got into it back there, didn’t you? Do you think that maybe that might have something to do with the … knot … gah, I can’t even say it, it feels so weird all of a sudden … do you think that might have had something do with the knot appearing out of thin air so to speak?”

Derek shrugged his shoulders, careful not to move his hips at all. “I really don’t know. Maybe? I do want children, I always have wanted to have children some day and I guess the wolf got a little overenthusiastic?”

Stiles exhaled loudly. “Somehow I imagined our “Do we eventually want children” discussion to go down slightly different,” he muttered and Derek tucked his chin in the crook of Stiles’ neck with a small smile.

“Yeah, me too. But since we’re not going anywhere for a while it seems – what _are_ your thoughts on the subject?”

Stiles shook his head. “I love you Sour Wolf, I really do, but can we please not discuss this while your magical knot is stuck in my butt, it’s making me really nervous.”

Derek tensed behind him and Stiles angled his chest so he had enough leverage to elbow Derek’s side, wincing when the movement tugged on the knot again.

“I can literally hear your brain yodeling while it’s jumping down the conclusion-cliff right now. Yes, Derek, I will eventually want children in the future. Preferably with you, if you must know. So how about we both relax, enjoy some cuddling and eventually you can … you’ve _got_ to be kidding me!”

Stiles’ attempt to sooth Derek’s anxieties had apparently been successful enough that the werewolf somehow managed to come again at Stiles’ confession that he did want kids with him. Judging by Derek’s harsh breathing and the trembling of his arms and legs, he was starting to get exhausted by the situation.

The head resting on his shoulder was getting heavier and Stiles could tell that Derek was about to fall asleep on him. He stroked Derek’s hand affectionately and gently nudged his chin towards Derek’s cheek.

“Derek?” he asked lightly and Derek grunted in response, obviously already half-asleep.

“I think your wolf’s breeding kink far outgrows mine – literally.”

“Call me Kinky Wolf in front of our friends and I will spank you. Literally,” Derek yawned sleepily and Stiles laughed.

He would never do that – probably.

It did indeed take about an hour for the knot to go down completely and once Derek pulled out Stiles felt both relieved and a little sad at the loss of intimacy. He gingerly stood up from the bed and winced when he started walking towards the bathroom. Derek was already standing in the shower and Stiles quietly slipped in behind him, wrapping himself around Derek and resting his chest against Derek’s broad back.

“So Derek – as nice as that was, I don’t think I want it to be a regular thing. Would that be ok?” he asked his boyfriend hesitantly and Derek chuckled. “I feel like I haven’t slept in a week so yes, that should probably not be a regular thing,” he agreed and Stiles sighed in relief.

******************

The rest of the weekend went by rather quickly and Stiles felt like the world’s biggest sap when he came back to his dorm room and curled up with a henley he had swiped from Derek’s closet just before leaving Beacon Hills.

Ever since the accidental knotting he felt even closer to Derek somehow and it hit him hard how much he actually missed his physical presence at university.

Classes were still keeping him on his toes and with another big project looming over his head before finals he had little time to reflect on their little fantasy-turned-reality escapade. On the night he and two of his classmates turned in their papers, Stiles convinced them to go to a bar with him, allowing himself to relax for the first time in well over a week. Lauren and Kyle, his closest friends at university and the most adorable couple besides him and Derek that Stiles had ever seen, didn’t need much arm-wrestling. They played a game of pool, had some shots, and took a stint to a nearby Karaoke bar, and when a drunk, slightly-sweaty Lauren wrapped herself around Stiles at one in the morning, smacked a big kiss on his cheek and declared him the best project-buddy ever, Stiles felt decidedly good about his life.

That good feeling lasted until approximately seven hours later, when Stiles found himself hunched over the toilet only moments after waking up, his stomach churning and cold sweat beading on his forehead.

He couldn’t remember ever feeling this sick, especially not after only one beer and two shots, and when he was done he pulled himself up shakily, splashed cold water on his face and stared into the bathroom mirror drowsily, his face pale and the bags under his eyes much more pronounced than normal. He was about to rinse out his mouth when the thought suddenly hit him, causing his knees to buckle and a fresh wave of nausea nearly overtook him.

“No way!” he breathed, his hands shaking as he grabbed his abdomen, suddenly very much aware of how the sudden movement made his sensitive stomach lurch unpleasantly.

“This is seriously not happening!”


	2. Chapter 2

When he told the story years later, Stiles always prided himself on the fact that he had managed to keep his anxiety in check for almost ten hours before giving in to a full-blown panic attack. After his terrifying epiphany in the bathroom he had stripped naked and inspected his stomach from all sides, breathing a sigh of relief when he couldn’t even find the hint of a bulge. It really wasn’t possible and he decided that there was definitely another explanation for his nausea, there had to be. In his mind he replayed everything he had ingested within the past 24 hours and finally decided that there must have been something off about the burrito he had shared with Kyle on their way back to the dormitories.

His stomach was still feeling sensitive when he made his way to his first class of the day. When the professor revealed that he had read over the first stack of proposals they had turned in the week before and was nothing short of disgusted at their abysmal writing skills and unimaginative ideas, his anxiety was briefly replaced by worrying about his grade for the class. He successfully pushed the thought to the back of his mind until his next class, which was one of the few he shared with Kyle. They met up for lunch in the cafeteria before, which might not have been the best idea since the smell of fried food made Stiles feel slightly queasy again.

Kyle was shoveling food into his mouth with gusto and Stiles tried not to read too much into it, arguing with himself that Kyle had always had a stronger stomach than anybody he knew, including even Derek with his fancy werewolf healing abilities. Classes dragged on throughout the day and Stiles was still successfully ignoring the nagging doubt in the back of his mind – and avoiding touching his stomach – when he walked into his last evening class at 5:15 PM. He sat down in the back of the lecture hall, sinking into the chair and massaging his temples when the two young women sitting next to him caught his attention.

They were animatedly discussing nursery designs and Stiles felt like he had been punched in the stomach when he realized that one of them was, at least to his untrained eye, heavily pregnant. He had seen her in class just last week, they had been paired up in a discussion group together, and she definitely hadn’t looked pregnant then. When she turned towards him and saw his flabbergasted look she grinned, holding up her hand when he tried to apologize for staring.

“I know, right?” she addressed Stiles, her hands cradling the impressive swell of her stomach affectionately, making him squirm in his seat even more. “This just happened all over night, I swear, with my first pregnancy you couldn’t see anything until I was almost seven months along, I had to show people the ultrasound picture with my name on the top before they’d even believe I was pregnant at all. But this time, it’s like I found out I was pregnant and poof, there’s the evidence.”

Stiles blanched. “So it’s normal that you can’t tell anything for the first couple of months?” he asked, his voice sounding higher than normal.

She laughed, clearly excited over a guy’s rather unusual interest in the inner workings of pregnancy. “Well, I think not showing until almost the seventh month was a bit unusual, but yes, it definitely takes a couple of months for most women to look pregnant with their first, even though you definitely feel it early on, you know, with all that nausea, the fatigue, and the sore breasts. It just takes a while for the muscles and tissue to relax so you actually start showing, you know, but with the second one your body already knows what’s going to happen so everything goes a bit faster … hey, are you alright?”

She trailed off, concern clear in her voice and if Stiles hadn’t been fighting the onset of a panic attack, he would have maybe tried to make an excuse as he shot up from his seat and sprinted out of class and towards the bathroom, his face white as a sheet and his nausea back full force. He barely made it into the little cubicle before he was once again retching, throwing up what little he had managed to eat during lunch.

When he was done he tugged his phone out of his pocket with shaking fingers and called Derek, trying and failing to control his breathing.

“Shouldn’t you be in class?” was the first thing Derek said when he picked up, his voice warm with amusement.

Stiles’ heart constricted in his chest when he heard his boyfriend and he breathed even quicker, a fact that didn’t go unnoticed by Derek, whose voice immediately turned from warm affection to concern.

“Stiles?! What’s wrong? Did something happen? Talk to me!” he demanded.

“Derek!” Stiles finally wheezed out, holding on to his right leg, which had started to shake uncontrollably.

“I think I’m pregnant!” he finally blurted out and for a moment Derek didn’t say anything.

When his voice came back through the tiny speaker he sounded exasperated. “Oh my god, Stiles, you can’t just call me sounding like some evil monster is about to kill and eat you just so you can tell me something ridiculous like that,” he exclaimed and Stiles shook his head frantically, despite the fact that Derek couldn’t see him.

“This is not a joke, trust me, _so_ not a joke, I threw up this morning and then I felt nauseous all day, and I couldn’t even eat my curly fries because the smell made me sick and Kyle could although he had the same burrito, and you don’t really show with your first pregnancy because of muscles and tissue or whatever and now I threw up again and Derek, I’m totally pregnant and …”

“Stiles!” Derek barked into his ear and he forced himself to breath in deeply, slowly releasing the air as he tried to remember every relaxation technique he had ever learned.

“Stiles, I don’t know what burritos, muscles and tissue have to do with this, but repeat after me. I. Am. A. Man. Men don’t get pregnant because they don’t have a uterus and they don’t have ovaries. Trust me, you don’t have girl parts, I checked. We’ve been over this. You can’t get pregnant.”

“You said you didn’t have a knot!” Stiles snapped, having regained enough control to get angry at Derek’s disregard of the gravity of the situation.

“You said you didn’t have a knot and look what happened! You knotted me and pumped like 2 liters of semen into me, clearly the same magic that gave you a knot could get me pregnant.”

He could hear Derek exhale as he tried to keep calm. “Stiles, there was no magic involved. I didn’t know about the knot because I was never supposed to be the Alpha, but I talked to Peter – and trust me, that was a conversation I would rather forget – and he finally decided to clue me in on one of the little useful items on his “Things Derek Should Know But I Won’t Tell Him Because I Love to See Him Fail”-List that he keeps around somewhere. It’s completely normal for Alphas to knot their mates when they want to start a family and …”

“See! You want to have a baby and your knot couldn’t tell the difference between boy parts and girl parts and now I’m pregnant and oh my god, Derek, I can’t give birth to a baby with my butt, I can’t …”

Derek interrupted him again, clearly regretting he had mentioned the part about starting a family.

“It’s completely normal for Alphas to knot their _female_ mates when they want to start a family. _Female_! You know, the part of the human population that has breasts and a vagina. Which you don’t! Again, I checked. I knotted you because you are my mate, but that doesn’t magically give you the parts necessary to conceive and grow a baby.”

He paused and Stiles could almost imagine him rolling his eyes at his panic. He didn’t appreciate it very much.

“Didn’t you say you were going to go out with Kyle and Lauren yesterday? I’m sure you only had a little too much to drink and that’s why you’ve been feeling nauseous all day.” Derek continued and Stiles huffed.

“A beer and two shots, Derek. That’s like a third of what I can manage without having a problem and it wasn’t the burrito either, because Kyle was totally fine. I’m telling you, I’m pregnant! My nipples feel super sore and oh god, Derek, I’m coming home right now!”

Derek sighed deeply, exasperation still clear in his voice, although a tinge of worry had crept back into it. “You are not driving when you are so close to freaking out. I’ll come get you and then I am going to take you to Melissa and she is going to explain to you, with charts if she has to, that men _don’t get pregnant._ ”

Stiles let out a shaky breath, suddenly having to fight back tears. “Ok,” he whispered, furiously wiping at his eyes. “Just come quickly, ok?”

“You are freaking out over nothing. I promise, it’s not possible.” Derek said, this time clearly more concerned than annoyed and Stiles could hear the jostling of his keys and the closing of a door, indicating that Derek was already on his way.

“Just come get me, ok?” he said and felt like actually bawling when he heard the car door open and close. “I’m on my way,” Derek said, before hanging up the call.

Shakily, Stiles picked himself off the floor and walked back to class, thankful that no one had been in the bathroom to overhear a conversation he couldn’t very well explain to someone who was unaware of the supernatural.

He quietly slipped into the lecture room, ignored the questioning and concerned looks of the two women, grabbed his backpack and made his way back to his dorm room, the cool evening air soothing his nerves just the tiniest bit.

 

*****************

 

Derek made the three hour drive in a little over 90 minutes and when Stiles opened his door to let him in, Derek took one look at his pale face and disheveled appearance before pulling him into a strong hug.

Stiles clung to Derek as if he was his lifeline and Derek rubbed soothing circles into his back, as if he was trying to calm a fussing baby. It was definitely the wrong mental image and Stiles could feel his heart speeding up again, which, of course, didn’t go unnoticed by Derek.

He held Stiles at arm’s length with one hand, the other coming up to cup his face, forcing him to actually look at Derek.

“Stiles. You need to calm down. Please.” His hands gently held onto Stiles’ waist as he leant in to sniff at Stiles’ neck, his nose moving over the sensitive skin before moving lower.

Derek dropped to his knees and he inhaled deeply as he sniffed at Stiles’ abdomen, his thumbs gently tracing up and down the younger man’s waist to keep him calm.

“Can you smell it?” Stiles asked, his voice barely a whisper. Derek rested his forehead against his stomach with a sigh, before pulling himself up and giving his boyfriend a serious look.

“I can’t smell anything because there is nothing to smell. There is no baby, there’s just you. You do smell a bit weird, but that’s probably because you are so freaked out but I promise you, there is no baby.”

“Well, how would you even know what a pregnant woman smells like?” Stiles pointed out and Derek groaned. “I did have a younger sister and besides, you would smell like a pregnant man, not like a pregnant woman, and men can’t get pregnant, which is why you _don’t_ smell pregnant.”

“But why do I feel so nauseous then?” Stiles argued and Derek gave him an incredulous look that seemed to say “Seriously?”

“Babe, you eat a shitload of crap all day long, you are surrounded by thousands of students who are carrying god knows what germs and you went out drinking last night. It’s surprising you don’t feel nauseous more often.” Derek said and Stiles grabbed his stomach, wincing as it once again rolled unpleasantly.

“That’s exactly my point, I never feel like this. Which is why it is in no way a coincidence that I am suddenly throwing up at all hours of the day five weeks after our little knotting-accident. I googled, this is exactly the point in time when the nausea would set in.”

Derek threw up his hands in frustration, his concern for his boyfriend having been replaced by annoyance once again now that he had made sure that Stiles wasn’t about to wrap his car around a tree on accident while driving home in a panic.

“I don’t know how often I have to repeat that men don’t get pregnant but I can see you are not going to listen to reason, which is why we are going home to Beacon Hills right now, where we’re going to have a long talk with Melissa tomorrow. We can get Deaton, too, I’d love to see him actually lose composure for once, which is what’s going to happen when you inform him of your imaginary pregnancy.”

Stiles actually looked hurt at his words and Derek sighed. “I’m sorry, I’m not trying to make fun of you, but Stiles … you _are_ being ridiculous.”

“You really need to work on your apologies,” Stiles snorted weakly, grabbing his already packed bag.

“There better be an apology of epic proportions coming my way when we confirm that your supposedly normal knot actually got me pregnant,” he muttered under his breath as they left the dorm and walked back toward Derek’s car, knowing full well that Derek could hear him.

Once he was seated in the car he immediately pulled out his cell phone and went through the fan fictions he had bookmarked in the last hour, reading out parts from the ones where the knotting was actually followed by a pregnancy.

Derek allowed him to ramble on about ass-babies, c-sections, and lactation kinks for all of ten minutes before he wrenched the phone out of Stiles’ hands and threw it onto the backseat, his glare warning his boyfriend that he did not want to hear another word.

Considering that the motion of the car made Stiles so nauseous that Derek had to pull over three times on the way to Beacon Hills, not talking was probably a good thing.

 

************

 

It was almost midnight by the time they got back to Beacon Hills and Stiles gave Derek a questioning look when he pulled up in front the Sheriff’s house instead of Derek’s building. The porch light went on and Stiles wasn’t ashamed to admit that he actually whimpered and tried to hide in his seat when his father stepped outside, looking at Derek’s car in confusion.

“Good evening John,” Derek said as he got out of the car, sounding altogether too casual and calm for Stiles’ liking, giving the severity of the situation.

“Derek,” the Sheriff said, his brows drawing together in confusion when he caught sight of Stiles, who was slowly exiting the Camaro. “Why is my kid not at university? And why does he look white as a sheet. Oh god, don’t tell me. Is it vampires?”

Derek looked back and forth between the Stilinski men, the look on his face clearly indicating that he had no idea why he deserved this. “No vampires John, you just seem to have forgotten to give your son the talk about the birds and the bees.”

The look on Stiles’ father’s face was priceless, confusion replaced by shock and then concern in quick succession.

“Excuse me? _What_ happened? Wait, do I even want to know?”

Derek had put his arm around Stiles’ waist and all but dragged his boyfriend to the front door, gently steering him past the Sheriff and leading him to the couch, where he lowered him onto the sofa.

“John,” he said, still sounding eerily calm and turning to his boyfriend’s father, who had followed them into the living room and sat down on the recliner facing the couch. “When Stiles was born, did he have both boy and girl parts and you decided to raise him as a boy without ever telling him?”

The Sheriff had just taken a sip from a glass of whiskey he had abandoned on the coffee table when he had heard the Camaro pull up and ended up spitting his drink all over the table.

“What?!” he sputtered, looking at Derek as if he had gone insane. “No! Of course not! Why would you even … Stiles, what the hell is going on? And why do you look like you’re about to throw up all over my couch? Did you take something? Is that why Derek brought you home? I swear, son, if you started doing drugs at College I will …”

“I’m pregnant,” Stiles whispered and immediately burst into tears.

Derek shot up from the couch, ready to perform CPR when the Sheriff grabbed at his chest and started coughing, but he held up his hand to indicate he was fine, his eyes widening when he looked at his son and his boyfriend.

“I’m sorry, I don’t think I heard that correctly. Come again?”

“I’m pregnant. I’ve been feeling sick all day and it wasn’t the burrito and I only had two shots and a beer last night, and now my nipples hurt and you don’t show early with your first pregnancy and oh my god, Dad, I’m so sorry,” Stiles sobbed and the Sheriff’s fatherly instincts kicked in as he moved to the side of the couch not currently occupied by Derek, putting an arm around his son’s shoulder and helpless patting his back.

The look he shot Derek was filled with confusion and Derek sighed, shaking his head in a way that he hoped conveyed that he had no idea why Stiles had suddenly gone insane.

“He keeps going on about the burrito, I have no clue why that’s so important,” Derek said, before placing his hand on Stiles’ knee.

“Stiles, if you don’t believe me, please listen to your father. You were not born with girl parts, you are not pregnant.”

He looked at the Sheriff in frustration when Stiles let out a low whine and burrowed his tear-soaked face in the Sheriff’s shirt.

“I was hoping you could calm him down, I can’t get him to understand that there is no way that he is pregnant.”

“Why would my son even _think_ that he is?” the Sheriff asked, his gaze accusatory as he glared at Derek over his armful of distraught son … his very manly son without female reproductive organs.

Derek had the good grace to blush. “Uhm … I’m not sure if you want to know.”

“I am certain I don’t but I am currently trying to comfort my hysterical son who thinks his supernatural creature boyfriend knocked him up, so yeah, I think you should probably tell me.”

Derek’s rubbed the palm of his hand over his face; clearly wishing he was anywhere else but here.

“Well, I didn’t find out about this until five weeks ago, but when an Alpha werewolf feels the natural urge to procreate,” Derek began, tactfully omitting the part about Stiles’ kinky fan fiction endeavors, “we apparently develop a … a knot, that makes sure that the semen doesn’t … uhm … leak out, and …”

The Sheriff held up a hand in protest, the look on his face close to physical pain.

“Alright, that’s enough. In other words, you accidentally developed this knot and now my son believes that the knot has magically turned his male reproductive organs into a uterus, correct?”

Derek nodded, grateful that the Sheriff had quickly pieced the information together.

John Stilinski took a deep breath and resolutely tugged at Stiles’ shoulders.

“Son, listen to me. You are freaking out and you are not thinking straight. Derek is right: men don’t get pregnant. You, however, used to throw up all the time as a little kid, especially in the car, which was not fun for all involved, trust me. If you had a burrito and two shots and …” he looked at Derek, who quickly mouthed “a beer” at him, before continuing “a beer, then your body is probably not taking that combination so well, especially given all the stress you have been under at university lately.”

He patted Stiles’ shoulder encouragingly. “What you need is a good night’s sleep, and tomorrow we are going to sit down and we are going to talk about condoms, because obviously that is something that we _really_ need to talk about” he glared at Derek while he said it and Derek winced “and then Derek is going to drive you back to university and we are all going to forget this conversation ever happened. Deal?”

Stiles sniffed, his eyes still brimming with tears, but he nodded, and the Sheriff pulled him into another quick hug, before gently nudging him towards Derek.

“Derek can stay here tonight, but I’m warning you, I don’t want to hear anything, I already have more traumatizing visuals in my head than I ever bargained for.”

Derek nodded and carefully pulled Stiles off the couch, mindful of his stomach, which was obviously still bothering the younger man, given his iron grip on his midsection and his pale complexion.

He gently tugged him upstairs and pulled back the covers while Stiles took off his shirt and pants. Derek crawled under the sheets and turned to his side so he could spoon his boyfriend, who was still sniffling quietly as he lay down next to Derek, his back pressed against Derek’s muscular stomach.

“I’m sorry,” Stiles whispered and Derek pulled him closer, his hand gently rubbing circles over Stiles’ belly in the hopes of soothing whichever ailment had brought on this bizarre situation.

“What are you sorry for?” Derek asked and Stiles made a small distressed sound in the back of his throat.

“For, you know, freaking out like this, and all the crying, and you having to come and get me. I just really don’t feel good at all today, I’m achy, and tired, and god, so fucking nauseous, and it just won’t stop. I know this shouldn’t be possible, I’m not stupid, but Derek, what if it is, what are we going to do if it _is_?”

Derek’s hand stilled for a second before he resumed stroking, his forehead pressed against the back of Stiles’ head.

“It’s not possible Stiles, and even if it was – which it _isn’t_ – did you think even for a second that I would leave you? Get angry with you? I want to have children with you eventually, I love you, but I promise you that when we do, they are not going to come out of you.”

He pressed a soft kiss to Stiles’ head and made himself more comfortable, his hand never leaving Stiles’ stomach. “It’s going to be fine,” he yawned and Stiles inhaled shakily, before nodding.

He focused on the soothing motions of Derek’s hand, the calming sound of his even breathing, and soon his exhaustion caught up with him and he sank into a deep sleep.

 

******************

 

When Stiles woke up the next morning he was still snuggled against Derek, the werewolf’s hand resting lightly on his midsection and his soft breathing indicating that he was still asleep. Blinking at the sunlight, the events of the last day came back to him and Stiles closed his eyes, his cheeks growing red with the memory. He had really freaked out, dragging both Derek and his _father_ into it and he almost winced at the thought of having to face his Dad this morning. Especially after tearfully declaring his imaginary pregnancy to him the night before and – now Stiles actually did wince – explaining the process of knotting to him.

He was never going to live that one down, that was for sure.

Behind him, Derek sighed contentedly, moving a little as he was slowly waking up and his sleep-slack grip on Stiles’ midsection tightened. It was only the slightest hint of pressure, but it made his stomach lurch and his arms and legs flailed frantically as he untangled himself from Derek’s grip, one hand coming up to press against his mouth desperately as he raced towards the bathroom, barely managing to pop up the toilet lid before he was throwing up violently.

His head hurt, his stomach hurt and now his throat hurt and he was helplessly grabbing his stomach while he retched, his eyes welling up with tears of pain and misery.

He barely registered Derek’s presence as the werewolf dropped to his knees behind him, barely noticed the hands rubbing his back and the concerned voices of his father and Derek over his head. When he felt somewhat sure that he was done, he fell back against Derek, an agonized whine escaping his lips as he rested his cheek against Derek’s chest.

“Not good, not good, so very not good,” he mumbled, still feeling too ill to have enough energy for anything else.

When he looked up his Dad, already dressed in his uniform, was leaning against the doorframe, his expression worried with a little hint of disbelief. Derek was still looking calm, stoically so, but Stiles’ back was pressed against his boyfriend’s chest and he could tell that Derek’s heart was pounding. He was obviously starting to get scared as well.

With a pitiful moan, Stiles jerked forward to throw up again.

He didn’t know who had told Scott, but suddenly his best friend was there as well, making the tiny bathroom decidedly crowded. Scott was out of breath; he had obviously just gotten the message and then sprinted all the way to the Stilinski residence.

“I just got a text that Stiles is ill and that something’s wrong, what’s going on?” he asked, frowning in confusion when all three men winced.

“Stiles has been throwing up for two days, it was neither the burrito, nor the two shots and one beer, there was a knotting accident a while back and we kind of need your mother’s help and use the ultrasound machine at the hospital.” Derek summarized the problem at hand and Scott looked at him like he had suddenly started singing a Spice Girls song.

“I’m sorry the what, because of what and what _knot_?” he stuttered and Derek stood up resolutely.

“I’m not in the mood to repeat it, you heard me. Can you help us or not,” he snapped, showing an outward sign of distress for the first time since he had gotten Stiles’ call yesterday.

Scott was blinking like an owl, his eyes drifting to Stiles’ father, looking like he hoped this was all a joke. The Sheriff shrugged, his expression resigned. “You’re the supernatural creature, not me, so how about you guys go and figure this out once and for all while I go to work and try not to worry about Derek having somehow managed to break my son.” He dropped to his knees in front of Stiles, pushing his sweaty hair out of his eyes and giving him an encouraging expression.

“I’m sure there’s an easy explanation kiddo, just keep it together for a bit longer, ok?”

The Sheriff stepped back so that Derek could bend down to cradle Stiles in his arms. He lifted him from the floor bridal style, as if he weighed nothing, and, after quickly helping him to get dressed, carried him to the car, closely followed by Scott, who had pulled out his cell phone to text his mother at the hospital and was still looking extremely confused about the whole thing.

Derek wordlessly tossed him the keys to the Camaro and let Scott slide behind the wheel, while he helped Stiles curl up into the tiny backseat of the sports car before sitting down on the passenger seat. He was turned halfway to the side, holding on to Stiles’ hand and his eyes never leaving the prone figure of his boyfriend. It was a sure sign that Derek was genuinely worried and Scott took a deep breath, figuring that at least one person should be calm about the whole thing.

“So … knotting?” he asked as he pulled onto the street and headed towards the hospital. The look Derek gave him from the side was pure evil and Stiles just moaned, his face hidden in the seat cushion.

“Let’s just say that if you ever feel like it would be awesome to have children, you should either put on a condom or have a serious conversation with Allison,” Derek said and Scott focused his eyes on the road, his mind suddenly assaulted by mental images he had never wanted to have.

When they got to the hospital parking lot, Scott turned around and carefully poked Stiles’ leg. “Stiles, buddy, Derek can’t carry you in there like that, the doctors will be all over you immediately and that will lead to questions that nobody wants to answer. I need you to try and either walk by yourself or we need to somehow smuggle you in on a gurney or something.”

Stiles shook his head; there was no way he was going to be wheeled in on a gurney. It took some effort but he managed to get out of the car with only little assistance, the fresh morning air helping him to clear his head a little and his skin had regained a hint of color by the time Scott led him past the nurses’ desk, checking his phone for a message from his mother.

Melissa was standing in front of an empty exam room; her arms crossed over her chest and her face a picture of incredulousness. The stern look in her eyes softened a bit when she took in Stiles’ pitiful appearance and she sighed, her hand going out to stroke over his hair, while the other checked his temperature.

“What did you boys manage to get yourself into this time,” she asked, the question almost rhetorical, as she did not wait for an answer but instead ushered them into the exam room. Both Derek and Stiles tensed at the sight of the ultrasound machine and Melissa shook her head, indicating for Stiles to lie down on the exam table.

“Now honey, I need you to pull up your shirt and push your pants down a little and then you need to tell me what exactly I am looking for, because Scott’s message just said “Stiles, ultrasound, stomach, now” and that really wasn’t very helpful. It’s also not the way to text your mother, especially not if you want her help, but we are going to talk about that later.”

Stiles cringed, helplessly looking towards Derek, who was still staring at the ultrasound machine as if it was a three-headed beast.

Scott looked between the two of them and, upon deciding that neither was in a state to answer his Mom’s question, he tried to answer as best as he could.

“Apparently there was some … uhm … biological misunderstanding and now we are worried that Stiles might be a little pregnant?”

Melissa, who had been in the process of setting up the machine, paused.

She slowly turned around to face her son, her expression full of disbelief.

“So what you are telling me is that Stiles, your best male friend, is ‘a little bit’ pregnant?”

She snorted. “First of all, you cannot be ‘a little bit’ pregnant, and secondly, please don’t tell me we either have to have that little talk from Junior High again or this is actually code and Allison is the one that’s pregnant. She’s not, right?” Melissa’s voice had risen up at the end and Stiles made a sound of protest, waving his arms a little to remind Melissa that he was in fact lying here on the exam table and that not everything revolved around Allison, even if it involved Scott.

Scott spluttered. “What, no! We don’t need to have the talk again and I’m serious, there was a problem with a knot and maybe some magic and …”

“I don’t even want to know,” Melissa interrupted him, before her gaze moved to Stiles and visibly softened.

“Honey, I’m going to squirt some gel on your stomach, it’s going to be a little cold, but that’s ok. Can you stay calm for me while we take a look inside?” she asked and Stiles nodded, his hand reaching out towards Derek, who immediately stepped closer and engulfed Stiles’ trembling hand with both of his.

For a moment they actually did look like anxious parents to be, but then Melissa shook herself out of her musings, reminding herself that she was, in fact, looking at two men, werewolf magic or not.

She moved the transducer probe over Stiles lower stomach, brows furrowed in concentration and both men followed her every move anxiously, while Scott was squinting at the screen alongside his mother.

“I don’t see anything,” he volunteered and Melissa hovered the probe under Stiles’ navel, coughing, to get the distraught man’s attention.

“Honey, I need you to listen very closely, ok? Do you hear a whooshing sound coming from the machine?”

Stiles concentrated and then shook his head.

“Do you see anything that looks like a baby or even a uterus on the screen?”

Stiles turned towards the screen, but before he could argue that there could be an elephant stumbling around in his intestines and he would have been none the wiser based on an ultra-sound image, Melissa had already removed the probe from his naked skin and was cleaning him up with a small towel.

“You can’t see anything on the screen because there is nothing there. There is no baby, you are not pregnant.”

“I told you so,” Derek muttered, his hand squeezing Stiles’ tightly and Scott’s head turned towards him sharply, as well as Melissa’s. By the look on Stiles’ face, he had also heard the small tinge of regret in Derek’s voice and he looked at him incredulously.

“Are you … are you upset Derek?” he asked quietly, and before Derek could answer, the door opened again, revealing Alan Deaton.

Talia Hale’s former emissary took in the scene in front of him, his eyes wandering from Stiles’ exposed stomach to Melissa’s gloved hands and then to Derek, who was blushing and refusing to look anyone in the eye.

“I seem to have missed the big reveal,” Deaton remarked, stepping inside and closing the door behind him. He walked over to Scott and gently nudged his upper arm, waving his phone at him with an amused look on his face.

“For the record, Scott, a text that says “Stiles, hospital, ass-babies, help” is more confusing than helpful, to be honest.”

Ignoring Stiles’ bristle at the mention of ass-babies, even though he himself had been thinking along the same terminology for the past 24 hours, Deaton grabbed a stool and sat down, facing Derek and Stiles with a somber expression on his face.

“Would you gentlemen care to explain to me why you had poor Melissa look for a non-existent baby in a human male’s stomach?” he asked politely and Melissa chuckled, the sound breaking some of the tension in the room.

“This is the part where I leave, as I said, I really don’t want to know.” She pulled her phone out of her pocket and smiled at Derek.

“I’m assuming you would like me to call John and tell him that he can stop researching wolf-castration techniques online, as his earlier text to me indicates he has been doing all morning?” she asked and Derek’s dark expression wavered, as the corners of his lips twitched just the tiniest bit.

“Yes please,” he said and Stiles laughed shakily, before groaning and putting one hand over his mouth while the other came to rest on his stomach, rubbing it gently.

“I still feel really, really nauseous though,” he commented.

Melissa went to check his temperature again, but before she could do so, Stiles’ phone buzzed. He gestured for Derek to pull it out of his jacket-pocket with a small frown, took a look at the message, and flopped back onto the exam table, yelping as his head hit the hard surface with a thump.

“I’m going to _kill_ her,” he groaned, holding his phone towards Derek, who took it from him and read Kyle’s message out loud.

“Hope you are not feeling ill today, Lauren has the worst case of stomach flu I have ever seen, she’s been throwing up since yesterday morning. Didn’t see you in class today so I thought I’d check.”

Derek slowly lowered the phone, his gaze unreadable and Melissa could hardly keep herself from laughing out loud.

“Oh honey,” she said, walking over towards the medicine cabinet and taking out a bottle of pills.

“Of _course_ it had to be a magical pregnancy, there was no way you were going to have a normal stomach bug,” she said, dropping some of the pills into Stiles’ hands.

“This might help with the nausea, you just need to make sure you drink enough to keep yourself hydrated. If it takes longer than three days call me, but all you really need right now is rest, plenty of fluids, and some tender loving care from some werewolves with excellent immune systems,” she grinned.

Stiles took the pills gratefully, looking more embarrassed by the second.

Derek stood up to get him a glass of water and when he sat back down, the sad expression had settled back over his face, leaving him looking a little lost.

Deaton cleared his throat.

“So Derek,” he said to the Alpha “since a knot usually only makes an appearance when a werewolf has made the conscious decision to procreate, I am assuming you have been thinking about having children,” he said gently and Derek, still refusing to look at anyone, nodded, his gaze fixed to the floor. 

“Really? How long?” Stiles interrupted and Derek sighed, his shoulders slumping a little.

“Ever since you said that thing about the Princess Tea Parties,” he mumbled, his cheeks coloring in embarrassment and Scott looked very confused again but Deaton held up his hand to keep him quiet.

“You know of course that you have chosen a male mate, which makes it impossible for you to impregnate him, even with him having the spark,” the vet explained and Derek nodded, eyes still trained on the floor but giving Stiles’ hand a gentle squeeze.

“I know. And I’m not upset we can’t have our own children, it’s just for a moment I thought … but that’s ok, we are not ready yet and when we are, eventually, maybe we can talk about adoption.”

Deaton smiled his trademark mysterious little smile.

“Who said you can’t have your own children,” he wondered out loud and three heads shot up to look at him, shocked expressions on their faces.

“Stiles cannot get pregnant, I believe we just saw his lack of a uterus on the screen over there. But Derek certainly can.”

The room was silent for a fraction of a second, before three voices rang out at once.

“But I don’t have a knot!”

“Does that mean Allison can knock me up?!”

“Are you sure?”

Deaton clapped his hands together to silence them, choosing to answer Derek’s question first.

“Yes Derek, I’m very sure. Becoming an Alpha changed many things about you, including giving you the physical equipment of carrying on the bloodline if you were to choose a male mate. It is not common, but it has been known to happen a few times over the past centuries. Obviously you would not be able to go to a normal hospital and I would definitely have to do some reading, but yes, you could definitely carry a child and if you were to do so, I would be glad to assist you throughout the pregnancy and the birth.”

He turned to Stiles next, nodding at the dumbstruck man.

“Yes, Stiles, you do not have a knot, but since your mate is an Alpha werewolf, you really don’t need one. Therefore, I suggest condoms for the foreseeable future, as it will take Derek’s wolf a while to get out of the breeding mode and you should be very careful if you were to engage in activities that could actually make that possible.”

Lastly, he focused on Scott, shaking his head and smirking at him.

“No, Scott, unless Allison has a hidden penis somewhere that she never told you about she will not be able to get you pregnant and I really shouldn’t have to explain that to somebody who is going to med school.”

“I want to be a vet and male sea horses _can_ get pregnant,” Scott argued, although his face was as red as a tomato.

Deaton shook his head again, looking resigned.

“Indeed they can. If that is all, gentlemen, there is a black Labrador waiting for my undivided attention at the clinic. Are you coming Scott? I suddenly have the inexplicable urge to have a fatherly talk with you about bees and birds – and not in the veterinarian sense.”

Scott gulped, his eyes screaming ‘help me’ at his best friend, but Stiles shook his head with a grin. He was still feeling a bit nauseous, but the pills were already helping and all in all he felt as if a huge weight had been lifted off his shoulders.

“Come on Sour Wolf,” he smiled at Derek, gently taking his hand as he gingerly stood up from the exam table.

“Let’s take me home to get me some tender loving care. And let’s hope I didn’t get my dad sick as well.”

 

******************

 

By the time they got home Stiles was feeling much better. He was still exhausted, but actually knowing that he wasn’t pregnant after all had done wonders for his physical state. Derek had been silent on their drive back and Stiles had decided to give him some space, considering the possibly life-altering information he had just received.

It was barely noon, but Stiles decided he wasn’t hungry and instead went up to crawl back into his bed. After taking off his shirt Derek joined him and they lay next to each other in silence for a while.

Eventually, Stiles turned onto his side and propped his head up with one hand, lightly placing his other hand on Derek’s chest.

“So … babies, huh?” he said and Derek breathed a soft laugh.

“Well, I did promise you that if we were ever going to have kids they were not going to be coming out of you,” he said and Stiles grinned sheepishly.

“That you did. And I can’t tell you how much of a relief that is.”

“I can tell,” Derek replied, stretching to fold his hands under his head.

“Yeah. But Derek … how do you feel about these hypothetical kids eventually coming out of _you_?”

Derek looked at him with a contemplative look on his face, removing one of his hands from under his head and almost automatically placing it on his stomach.

“I don’t really know yet. My head is still saying ‘men don’t get pregnant’, but my instincts are already telling me that this is exactly what I should do. It’s a little weird, but I think I’ll get used to the idea. What about you?”

The look in Derek’s eyes was almost fearful when he asked and Stiles gently traced his fingers down Derek’s body, until he could intertwine his fingers with Derek’s on his stomach.

“I told you weeks ago that you would be an amazing father and I told you that I want to have children with you at some point in the future. How they come to happen doesn’t really matter to me, to be honest. And if it won’t make you feel emasculated or anything like that, and if you are truly willing to go through a supernatural Alpha werewolf pregnancy so that we can have a family … Derek, I love you so much, there is no way I could say no to that.”

Derek pressed a soft kiss to Stiles’ brow in response.

“Good.”

They snuggled in silence for a while, Stiles’ hand gently tracing circles on Derek’s lower belly and Derek’s hand lightly resting on top of his.

“Stiles?”

“Yes Derek?”

“There will be no fan fiction dialogue when we conceive our children.”

Stiles laughed.

“That’s ok, I never could manage a decent growl anyways.”

**Notes for the Chapter:**

> The end - probably not what some of you were expecting ;-).
> 
> However, mpreg is absolutely possible in the Alliteration-Verse, and, depending on whether I feel a sudden onset of actual mpreg-writing-skills, there might be a sequel to this at some point in the future.

**Author's Note:**

> Next Up:
> 
> Is he, or isn’t he? Stiles is freaking out, Derek tries – and fails – to be the voice of reason, Scott wants to be helpful, and Melissa and the Sheriff end up equal parts confused and traumatized.
> 
> P.S: I tumble now, come and say hi! 
> 
> http://kaliopeshipsit.tumblr.com/


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